gregfjohnson

6 ms·

1.
by gregfjohnson 1mo ago
Glad to! I put them on https://gregfjohnson.com/godel_incompleteness.pdf
2.
by gregfjohnson 1mo ago
Show HN: I recently gave a talk on the incompleteness theorem, specifically expressed in the language of software. It starts with a bit of historical background and a discussion of some of the philosophical context in which he carried out
3.
by gregfjohnson 1mo ago
Joel Hamkins is my new favorite mathematician :-) There is a beautiful application of the power set of the Naturals to denotational semantics. I assume Prof. Hamkins's book will cover that topic, but it is not mentioned in the linked
4.
by gregfjohnson 2mo ago
Been doing this for 20 minutes in the morning for a few decades now. It has had an impact. I am a rather “high gain” person emotionally. I now tend to notice emotions and observe them, which helps when they threaten to suck me into a sel
5.
by gregfjohnson 2mo ago
It is a surprising and delightful consequence of this observation that there is a polynomial whose integer-valued roots are exactly the set of all prime numbers.
6.
by gregfjohnson 6mo ago
(Show HN?) There is a deep and lovely connection between the Y-combinator and the classic version of Godel's incompleteness theorem: https://gregfjohnson.com/incompleteness/
7.
by gregfjohnson 8mo ago
One use case that I'm beginning to find useful is to go into a specific directory of code that I have written and am working on, and ask the AI agent (Claude Code in my case) "Please find and list possible bugs in the code in this
8.
by gregfjohnson 8mo ago
This all reminds me of one of the most foundational and profound papers ever written about software development: Peter Naur's "Programming as Theory Building". I have seen colleagues get excited about using Claude to write
9.
by gregfjohnson 8mo ago
https://gregfjohnson.com
10.
by gregfjohnson 9mo ago
The original comment by Rob Pike and discussion here have implied or used the word "evil". What is a workable definition of "evil"? How about this: Intentionally and knowingly destroying the lives of other people for no
11.
by gregfjohnson 9mo ago
Build one yourself! Here's an interactive balanced binary tee builder: https://gregfjohnson.com/redblackbuilder.html
12.
by gregfjohnson 9mo ago
(Show HN?) Here is another attempt at providing intuition on complex numbers, the multiplication rule in particular: "Why does complex multiplication have to be the way it is?" https://gregfjohnson.com/complex&#x2F
13.
by gregfjohnson 10mo ago
There are bitter and heartstrong arguments on this topic. Brachycephalic breeds with flat faces or short snouts (for example pugs, bulldogs, boxers, Boston terriers) cause anger among some and devotion among others. (We are a three-pug fa
14.
by gregfjohnson 1y ago
There is this wonderful concept of "flow state", which I'm sure most of us are familiar with. It was originated by Mihaly Csikszentmihalyi. Many of us in this thread (and Linus's essay quoted in OP) are referring in va
15.
by gregfjohnson 1y ago
My programming brain has two modes. One is playful mode, and the other is drudge workaday mode. 9-to-5 Monday through Friday is workaday mode. Other times are playful mode. As it turns out, I am a far better programmer in one of those t
16.
by gregfjohnson 1y ago
I heard an interesting talk recently by a Stanford neuroscientist. He was studying standing waves of brain activity among circularly linked groups of neurons. Neurons can provide both excitatory inputs and inhibitory inputs to other neuron
17.
by gregfjohnson 1y ago
I hacked up a version of minesweeper that was “forgiving:” if there was no selection that was provably safe, it gave you a safe move. If you picked any square that was not provably a bomb, it would not be a bomb. Typically, as long as you
18.
by gregfjohnson 1y ago
On the topic of Microchip and secrecy: I downloaded and installed their IDE, MPLAB X IDE v6.20. It is for a pic3mx chip. The compiler looks like a completely generic gcc, built to cross-compile on a Windows host. However, they want a $1
19.
by gregfjohnson 1y ago
I wonder if there are any plans to place meat along the bridge to attract mountain lions. Will ecologists try to "train" the wildlife to use the bridge, or just let nature take its course?
20.
by gregfjohnson 1y ago
One possible definition of "random" in this context: Is there any conceivable algorithm, perhaps one that models the entire universe in all of its particulars, that predicts the next string produced by the NIST quantum beacon?
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by gregfjohnson 2y ago
PuTTY is a supurb tool. Thank you so much for your efforts over the years.
22.
by gregfjohnson 2y ago
IBM wrote APL\360 in 360 assembly language. The IBM 5100 personal computer had a small cpu. They wanted APL on the 5100, so they implemented a 360 emulator and ran the original implementation of APL on that.
23.
by gregfjohnson 2y ago
OK here is my attempt at intuition: Here is an approximation that captures the main effect (the 23.5 degree tilt of the earth's rotation axis) and overlooks secondary effects. Consider the equator. Imagine a circle on the X-Y plane ce
24.
by gregfjohnson 2y ago
Thanks, very much appreciate the thoughts and pointers!
25.
by gregfjohnson 2y ago
This brings to mind something I've wondered about for a while. Sunrise on the shortest day of the year is earlier than sunrise for several days after it. Sunset on these days after the shortest day is of course even later than sunset
26.
by gregfjohnson 2y ago
I've been trying to find discussion of this topic on Hacker News between October 1582 and September 1752, but to no avail. 'cal 9 1752' is .. funny. I guess instead of doing this annoying a-periodic leap second business, the
27.
by gregfjohnson 2y ago
This short book is (IMHO) one of the best on software design. To me the main point of the book is the importance of well-designed abstractions. The "surface area" of a well-designed abstraction is small, easy to understand, and
28.
by gregfjohnson 2y ago
This same identity can be used to provide geometric intuition as to why i*i must equal -1. This is shown in the diagrams at the bottom of http://gregfjohnson.com/complex/ .
29.
by gregfjohnson 2y ago
A nice way to think about eta-reduction is that it asserts something about the types of expressions in lambda calculus, namely that every expression is in fact a function. If an expression M can appear in the left position of the function a
30.
by gregfjohnson 2y ago
I work at a medical device company that specializes in radiation treatment for brain tumors. This thoughtful and profound essay brings home the lived reality of the patients who are treated by our systems. The writer speaks lived truth that

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